A torsional vibration damper is utilized, for example, in the drivetrain of a motor vehicle, in order to transmit torque between an input side and an output side. The input side is usually designed to introduce a torque from a drive motor, and the output side is designed to pass the torque on to a gear unit, the torque usually being transmitted in both directions. The transmission of torque occurs elastically in this case, in order to isolate torsional vibrations between the input side and the output side. The torsional vibrations may be caused in particular by non-uniform torque output from the drive motor, particularly in the case of a reciprocating internal combustion engine.
To transmit the torque elastically between the input side and the output side, an arc spring may be used, which is situated on a segment of a circumference around an axis of rotation on the input side and the output side. If the input side is rotated relative to the output side, the arc spring is compressed along the circumference. In order to prevent the arc spring from migrating radially outward, caused by the compression or by centrifugal forces, a holding element in the form of a so-called retainer is provided.
In order to transmit compression forces between the input side and the one end of the arc spring, or between the output side and the other end of the arc spring, an end cap may be provided on one or both sides of the arc spring. Depending on the design, the end cap may convey axial, or, in addition, radial forces to the arc spring. Known end caps are produced by means of a machining production process, such as turning, or by extrusion. Both fabrication methods involve relatively high production costs, and limit mass production of the end caps. Furthermore, end caps of this sort involve the use of a relatively large amount of material, so that the mass of the end caps is relatively great, which contributes to a high rotating mass of the torsional vibration damper.